No, selling on marketplaces does not require a website. And it is even one of the interests of marketplaces : To be able to sell products on the internet without deploying a site.
On the vast majority of marketplaces, having your own site is not necessary. Many sellers and brands only sell on marketplaces and have no website or even physical stores.
However, having your own site is useful for reassuring customers and enhancing your brand image. It may be wise to create a “catalog” site in order to have a good understanding of the content and to refer to marketplaces to trigger online sales .
A solution like Sellermania allows you to connect to marketplaces without a website and without flow . Everything is manageable from Sellermania. It is also possible to switch from one to the other: manage without a site, then manage with a website, or vice versa.